1. Field of Invention
This invention relates to fuel control systems for spark ignition engines in general and to fuel metering systems controlling the fuel-air ratio in the throttle body of the engine.
2. Background of Invention
Fuel control systems for internal combustion engines, other than the conventional carburetor mixing systems, are based on the fuel injection concepts of compression ignition engines. In this type of engine, such as a diesel engine, fuel is directly injected into each cylinder of the engine. Spark ignition engines have this concept extended to injecting fuel into the inlet to each cylinder.
One disadvantage of fuel injection as described above is the requirement of having a somewhat precision injector for each cylinder. This increases the cost of such a system to such a magnitude that makes the system unattractive in the general market place. In addition, control of these injectors is generally responsive to manifold vacuums and engine speeds.
The amount of fuel each cylinder receives is a function of injector timing and not the actual rate of fuel flow. Thus, each cylinder will receive an amount of fuel which may or may not be the desired amount for good combustion.